1. Field of the Invention
The present invention relates to the technical field of optical storages and, more particularly, to a cyclic video recording method for an optical storage medium and an optical storage using the same.
2. Description of Related Art
In various video recording applications such as monitor systems, the system has to sequentially record a video in real time on a limited storage space and also play the video. Thus, the prior art cyclically uses the limited storage space to store, query and playback the content recorded within a certain range of period from the present time.
Upon the features of high capacity, low price and popularity of an optical storage medium, the optical storage medium is very suitable for recording applications such as monitor systems. However, due to the read/write characteristics on the optical storage medium and the comparably longer mechanical seek time, it is limited and hard to implement the real-time sequential recording and playback by using the optical storage medium cyclically.
In the prior art, a write operation is performed on the optical storage medium for sequentially recording video data from low to high addresses. For the physical mechanical movement of the pickup of an optical storage, such a write operation is performed by the optical storage on the optical storage medium from the inner circle to the outer circle. When the limited space on the optical storage medium is cyclically used, the write operation suffers the problem of discontinuous recording. As shown in FIG. 1, when a write operation on the optical storage medium 110 reaches to the highest address LBAmax, the optical storage re-locates a writing position by drawing the pickup 120 from the highest address LBAmax to the lowest address LBAmin. Namely, the pickup 120 is moved on the optical storage medium 110 from the outer edge to the inner edge and continues the write operation at the lowest address LBAmin to thereby obtain the cyclic space usage. When the optical storage is drawing the pickup 120 from the outer edge to the inner edge, it performs a long seek operation. The long seek operation performs a mechanical action and associated adjustments on the pickup 120. Such a mechanical action takes much time. Similarly, the discontinuousness of recorded images is met when the write operation cyclically records the images on the optical storage medium.
To overcome the discontinuousness problem, the prior art increases the amount of buffers to the optical storage in order to temporarily store the recording images. However, such a manner relatively increases the hardware cost of the optical storage. In addition, when the pickup 120 reaches to the highest address LBAmax during a playback, the optical storage has to draw the pickup 120 from the highest address LBAmax to the lowest address LBAmin, which similarly produces the discontinuousness.
Therefore, it is desirable to provide an improved video recording method to mitigate and/or obviate the aforementioned problems.